/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
//package org.apache.dubbo.registry.client;
//
//import com.alibaba.fastjson.JSON;
//import org.apache.commons.io.FileUtils;
//import org.apache.dubbo.common.URL;
//import org.apache.dubbo.common.config.configcenter.ConfigChangedEvent;
//import org.apache.dubbo.common.config.configcenter.file.FileSystemDynamicConfiguration;
//import org.apache.dubbo.common.lang.ShutdownHookCallbacks;
//import org.apache.dubbo.common.logger.Logger;
//import org.apache.dubbo.common.logger.LoggerFactory;
//import org.apache.dubbo.common.utils.StringUtils;
//
//import java.io.File;
//import java.io.IOException;
//import java.nio.channels.FileChannel;
//import java.nio.channels.FileLock;
//import java.nio.file.LinkOption;
//import java.nio.file.Path;
//import java.nio.file.StandardOpenOption;
//import java.util.List;
//import java.util.Map;
//import java.util.Set;
//import java.util.concurrent.ConcurrentHashMap;
//import java.util.stream.Collectors;
//
//import static com.alibaba.fastjson.JSON.toJSONString;
//import static java.lang.String.format;
//import static java.nio.channels.FileChannel.open;
//import static org.apache.dubbo.common.config.configcenter.DynamicConfiguration.DEFAULT_GROUP;
//import static org.apache.dubbo.common.config.configcenter.file.FileSystemDynamicConfiguration.CONFIG_CENTER_DIR_PARAM_NAME;
//
///**
// * File System {@link ServiceDiscovery} implementation
// *
// * @see FileSystemDynamicConfiguration
// * @since 2.7.5
// */
//public class FileSystemServiceDiscovery extends AbstractServiceDiscovery {
//
//    private final Logger logger = LoggerFactory.getLogger(getClass());
//
//    private final Map<File, FileLock> fileLocksCache = new ConcurrentHashMap<>();
//
//    private FileSystemDynamicConfiguration dynamicConfiguration;
//
//    public FileSystemServiceDiscovery(String serviceName) {
//        super(serviceName);
//    }
//
//    @Override
//    public void doInitialize(URL registryURL) throws Exception {
//        dynamicConfiguration = createDynamicConfiguration(registryURL);
//        registerDubboShutdownHook();
//        registerListener();
//    }
//
//    private void registerDubboShutdownHook() {
//        serviceInstance.getApplicationModel().getBeanFactory().getBean(ShutdownHookCallbacks.class)
//            .addCallback(this::destroy);
//    }
//
//    private void registerListener() {
//        getServices().forEach(serviceName -> {
//            dynamicConfiguration.getConfigKeys(DEFAULT_GROUP).forEach(serviceInstanceId -> {
//                dynamicConfiguration.addListener(serviceInstanceId, serviceName, this::onConfigChanged);
//            });
//        });
//    }
//
//    public void onConfigChanged(ConfigChangedEvent event) {
//
//    }
//
//    @Override
//    public void doDestroy() throws Exception {
//        dynamicConfiguration.close();
//        releaseAndRemoveRegistrationFiles();
//    }
//
//    private void releaseAndRemoveRegistrationFiles() {
//        fileLocksCache.keySet().forEach(file -> {
//            releaseFileLock(file);
//            removeFile(file);
//        });
//    }
//
//    private void removeFile(File file) {
//        FileUtils.deleteQuietly(file);
//    }
//
//    private String getServiceInstanceId(ServiceInstance serviceInstance) {
//        String id = serviceInstance.getAddress();
//        if (StringUtils.isBlank(id)) {
//            return serviceInstance.getHost() + "." + serviceInstance.getPort();
//        }
//        return id;
//    }
//
//    private String getServiceName(ServiceInstance serviceInstance) {
//        return serviceInstance.getServiceName();
//    }
//
//    @Override
//    public List<ServiceInstance> getInstances(String serviceName) {
//        return dynamicConfiguration.getConfigKeys(DEFAULT_GROUP)
//                .stream()
//                .map(serviceInstanceId -> dynamicConfiguration.getConfig(serviceInstanceId, serviceName))
//                .map(content -> JSON.parseObject(content, DefaultServiceInstance.class))
//                .collect(Collectors.toList());
//    }
//
//    @Override
//    public URL getUrl() {
//        return null;
//    }
//
//
//    @Override
//    public void doRegister(ServiceInstance serviceInstance) throws RuntimeException {
//        this.serviceInstance = serviceInstance;
//        String serviceInstanceId = getServiceInstanceId(serviceInstance);
//        String serviceName = getServiceName(serviceInstance);
//        String content = toJSONString(serviceInstance);
//        if (dynamicConfiguration.publishConfig(serviceInstanceId, serviceName, content)) {
//            lockFile(serviceInstanceId, serviceName);
//        }
//    }
//
//    private void lockFile(String serviceInstanceId, String serviceName) {
//        File serviceInstanceFile = serviceInstanceFile(serviceInstanceId, serviceName);
//        Path serviceInstanceFilePath = serviceInstanceFile.toPath();
//
//        fileLocksCache.computeIfAbsent(serviceInstanceFile, file -> {
//            FileLock fileLock = null;
//            try {
//                FileChannel fileChannel = open(serviceInstanceFilePath, StandardOpenOption.READ, StandardOpenOption.WRITE, LinkOption.NOFOLLOW_LINKS);
//                fileLock = fileChannel.tryLock();
//            } catch (IOException e) {
//                if (logger.isErrorEnabled()) {
//                    logger.error(e.getMessage(), e);
//                }
//            }
//            if (fileLock != null) {
//                if (logger.isInfoEnabled()) {
//                    logger.info(format("%s has been locked", serviceInstanceFilePath.toAbsolutePath()));
//                }
//            }
//            return fileLock;
//        });
//    }
//
//    @Override
//    public void doUnregister() throws RuntimeException {
//        String key = getServiceInstanceId(serviceInstance);
//        String group = getServiceName(serviceInstance);
//        releaseFileLock(key, group);
//        dynamicConfiguration.removeConfig(key, group);
//    }
//
//    private void releaseFileLock(String serviceInstanceId, String serviceName) {
//        File serviceInstanceFile = serviceInstanceFile(serviceInstanceId, serviceName);
//        releaseFileLock(serviceInstanceFile);
//    }
//
//    private void releaseFileLock(File serviceInstanceFile) {
//        fileLocksCache.computeIfPresent(serviceInstanceFile, (f, fileLock) -> {
//            releaseFileLock(fileLock);
//            if (logger.isInfoEnabled()) {
//                logger.info(format("The file[%s] has been released", serviceInstanceFile.getAbsolutePath()));
//            }
//            return null;
//        });
//    }
//
//    private void releaseFileLock(FileLock fileLock) {
//        try (FileChannel fileChannel = fileLock.channel()) {
//            fileLock.release();
//        } catch (IOException e) {
//            if (logger.isErrorEnabled()) {
//                logger.error(e.getMessage(), e);
//            }
//        }
//    }
//
//    private File serviceInstanceFile(String serviceInstanceId, String serviceName) {
//        return dynamicConfiguration.configFile(serviceInstanceId, serviceName);
//    }
//
//    @Override
//    public Set<String> getServices() {
//        return dynamicConfiguration.getConfigGroups();
//    }
//
//    private static FileSystemDynamicConfiguration createDynamicConfiguration(URL connectionURL) {
//        String path = System.getProperty("user.home") + File.separator + ".dubbo" + File.separator + "registry";
//        return new FileSystemDynamicConfiguration(connectionURL.addParameter(CONFIG_CENTER_DIR_PARAM_NAME, path));
//    }
//}
